<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        body{
            display: flex;
            flex-wrap: wrap;
        }
        div{
            height: 100px;
            background-color: yellow;
            border: 2px solid red;
            box-sizing: border-box;
            width: 33.33%;
        }
        /* orientation:portrait竖屏状态下 */
        @media screen and (orientation:portrait){
            div{
                width: 33.33%;
                /* background-color: gray; */
            }
        }
        /* orientation:landscape横屏状态下 */
        @media screen and (orientation:landscape){
            div{
                width: 20%;
                /* background-color: hotpink; */
            }
        }
    </style>
</head>
<body>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
</body>
</html>